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1da2738f AL |
1 | /* |
2 | * QEMU Random Number Generator Backend | |
3 | * | |
4 | * Copyright IBM, Corp. 2012 | |
5 | * | |
6 | * Authors: | |
7 | * Anthony Liguori <aliguori@us.ibm.com> | |
8 | * | |
9 | * This work is licensed under the terms of the GNU GPL, version 2 or later. | |
10 | * See the COPYING file in the top-level directory. | |
11 | */ | |
12 | ||
9c058332 | 13 | #include "qemu/osdep.h" |
dccfcd0e | 14 | #include "sysemu/rng.h" |
4d43a603 | 15 | #include "chardev/char-fe.h" |
da34e65c | 16 | #include "qapi/error.h" |
7b1b5d19 | 17 | #include "qapi/qmp/qerror.h" |
0b8fa32f | 18 | #include "qemu/module.h" |
db1015e9 | 19 | #include "qom/object.h" |
1da2738f AL |
20 | |
21 | #define TYPE_RNG_EGD "rng-egd" | |
db1015e9 | 22 | typedef struct RngEgd RngEgd; |
8110fa1d EH |
23 | DECLARE_INSTANCE_CHECKER(RngEgd, RNG_EGD, |
24 | TYPE_RNG_EGD) | |
1da2738f | 25 | |
db1015e9 | 26 | struct RngEgd { |
1da2738f AL |
27 | RngBackend parent; |
28 | ||
32a6ebec | 29 | CharBackend chr; |
1da2738f | 30 | char *chr_name; |
db1015e9 | 31 | }; |
1da2738f | 32 | |
60253ed1 | 33 | static void rng_egd_request_entropy(RngBackend *b, RngRequest *req) |
1da2738f AL |
34 | { |
35 | RngEgd *s = RNG_EGD(b); | |
60253ed1 | 36 | size_t size = req->size; |
1da2738f AL |
37 | |
38 | while (size > 0) { | |
39 | uint8_t header[2]; | |
40 | uint8_t len = MIN(size, 255); | |
41 | ||
42 | /* synchronous entropy request */ | |
43 | header[0] = 0x02; | |
44 | header[1] = len; | |
45 | ||
6ab3fc32 DB |
46 | /* XXX this blocks entire thread. Rewrite to use |
47 | * qemu_chr_fe_write and background I/O callbacks */ | |
5345fdb4 | 48 | qemu_chr_fe_write_all(&s->chr, header, sizeof(header)); |
1da2738f AL |
49 | |
50 | size -= len; | |
51 | } | |
1da2738f AL |
52 | } |
53 | ||
1da2738f AL |
54 | static int rng_egd_chr_can_read(void *opaque) |
55 | { | |
56 | RngEgd *s = RNG_EGD(opaque); | |
443590c2 | 57 | RngRequest *req; |
1da2738f AL |
58 | int size = 0; |
59 | ||
443590c2 | 60 | QSIMPLEQ_FOREACH(req, &s->parent.requests, next) { |
1da2738f AL |
61 | size += req->size - req->offset; |
62 | } | |
63 | ||
64 | return size; | |
65 | } | |
66 | ||
67 | static void rng_egd_chr_read(void *opaque, const uint8_t *buf, int size) | |
68 | { | |
69 | RngEgd *s = RNG_EGD(opaque); | |
1eb1bd9e | 70 | size_t buf_offset = 0; |
1da2738f | 71 | |
443590c2 LP |
72 | while (size > 0 && !QSIMPLEQ_EMPTY(&s->parent.requests)) { |
73 | RngRequest *req = QSIMPLEQ_FIRST(&s->parent.requests); | |
1da2738f AL |
74 | int len = MIN(size, req->size - req->offset); |
75 | ||
1eb1bd9e AK |
76 | memcpy(req->data + req->offset, buf + buf_offset, len); |
77 | buf_offset += len; | |
1da2738f AL |
78 | req->offset += len; |
79 | size -= len; | |
80 | ||
81 | if (req->offset == req->size) { | |
1da2738f AL |
82 | req->receive_entropy(req->opaque, req->data, req->size); |
83 | ||
9f14b0ad | 84 | rng_backend_finalize_request(&s->parent, req); |
1da2738f AL |
85 | } |
86 | } | |
87 | } | |
88 | ||
1da2738f AL |
89 | static void rng_egd_opened(RngBackend *b, Error **errp) |
90 | { | |
91 | RngEgd *s = RNG_EGD(b); | |
0ec7b3e7 | 92 | Chardev *chr; |
1da2738f AL |
93 | |
94 | if (s->chr_name == NULL) { | |
c6bd8c70 MA |
95 | error_setg(errp, QERR_INVALID_PARAMETER_VALUE, |
96 | "chardev", "a valid character device"); | |
1da2738f AL |
97 | return; |
98 | } | |
99 | ||
32a6ebec MAL |
100 | chr = qemu_chr_find(s->chr_name); |
101 | if (chr == NULL) { | |
75158ebb MA |
102 | error_set(errp, ERROR_CLASS_DEVICE_NOT_FOUND, |
103 | "Device '%s' not found", s->chr_name); | |
1da2738f AL |
104 | return; |
105 | } | |
32a6ebec MAL |
106 | if (!qemu_chr_fe_init(&s->chr, chr, errp)) { |
107 | return; | |
108 | } | |
456d6069 | 109 | |
1da2738f | 110 | /* FIXME we should resubmit pending requests when the CDS reconnects. */ |
5345fdb4 | 111 | qemu_chr_fe_set_handlers(&s->chr, rng_egd_chr_can_read, |
81517ba3 | 112 | rng_egd_chr_read, NULL, NULL, s, NULL, true); |
1da2738f AL |
113 | } |
114 | ||
115 | static void rng_egd_set_chardev(Object *obj, const char *value, Error **errp) | |
116 | { | |
117 | RngBackend *b = RNG_BACKEND(obj); | |
118 | RngEgd *s = RNG_EGD(b); | |
119 | ||
120 | if (b->opened) { | |
c6bd8c70 | 121 | error_setg(errp, QERR_PERMISSION_DENIED); |
1da2738f | 122 | } else { |
abb4d5f2 | 123 | g_free(s->chr_name); |
1da2738f AL |
124 | s->chr_name = g_strdup(value); |
125 | } | |
126 | } | |
127 | ||
128 | static char *rng_egd_get_chardev(Object *obj, Error **errp) | |
129 | { | |
130 | RngEgd *s = RNG_EGD(obj); | |
0ec7b3e7 | 131 | Chardev *chr = qemu_chr_fe_get_driver(&s->chr); |
1da2738f | 132 | |
5345fdb4 MAL |
133 | if (chr && chr->label) { |
134 | return g_strdup(chr->label); | |
1da2738f AL |
135 | } |
136 | ||
137 | return NULL; | |
138 | } | |
139 | ||
140 | static void rng_egd_init(Object *obj) | |
141 | { | |
142 | object_property_add_str(obj, "chardev", | |
d2623129 | 143 | rng_egd_get_chardev, rng_egd_set_chardev); |
1da2738f AL |
144 | } |
145 | ||
146 | static void rng_egd_finalize(Object *obj) | |
147 | { | |
148 | RngEgd *s = RNG_EGD(obj); | |
149 | ||
1ce2610c | 150 | qemu_chr_fe_deinit(&s->chr, false); |
1da2738f | 151 | g_free(s->chr_name); |
1da2738f AL |
152 | } |
153 | ||
154 | static void rng_egd_class_init(ObjectClass *klass, void *data) | |
155 | { | |
156 | RngBackendClass *rbc = RNG_BACKEND_CLASS(klass); | |
157 | ||
158 | rbc->request_entropy = rng_egd_request_entropy; | |
1da2738f AL |
159 | rbc->opened = rng_egd_opened; |
160 | } | |
161 | ||
8c43a6f0 | 162 | static const TypeInfo rng_egd_info = { |
1da2738f AL |
163 | .name = TYPE_RNG_EGD, |
164 | .parent = TYPE_RNG_BACKEND, | |
165 | .instance_size = sizeof(RngEgd), | |
166 | .class_init = rng_egd_class_init, | |
167 | .instance_init = rng_egd_init, | |
168 | .instance_finalize = rng_egd_finalize, | |
169 | }; | |
170 | ||
171 | static void register_types(void) | |
172 | { | |
173 | type_register_static(&rng_egd_info); | |
174 | } | |
175 | ||
176 | type_init(register_types); |